This invention relates to a motion analysis system in general and more particularly to a real time motion analysis system for monitoring motion regarding gait and monitoring responses of a patient's foot and legs.
The art of motion analysis has been investigated and there exists many prior art systems which serve and operate to analyze motion. Such which are based on computer programs operating in conjunction with complicated algorithms. The compute decodes and deciphers data according to such algorithms in order to determine the motion patterns of an individual.
According to the operation of such systems various body processes such as the motion and angles between body joints can be analyzed while a patient or a person is performing a typical task. This task may relate to a person's gait while walking and such systems may further monitor the movement of joints such as the knee, toe and so on.
Human motion analysis allows one to determine limits and constraints on various body joints and use such determinations to assist the patient in performing physical activities more efficiently. As one can ascertain from the prior art, most systems employ video cameras and a tape recorder to record the events and retain suitable pictures which are analyzed by the practitioner to determine the extent of motion.
This data can be placed in a computer which based on the programs can reconstruct the motion in terms of various configurations such as stick figure configurations or other configurations which are widely employed and known. As indicated, the prior art is replete with various system which analyze human motion and which systems employ video television cameras and video recorders to process data emanating from such devices in order to generate meaningful computer displays.
See for example, an article entitled "An Automated Motion Measurement System For Clinical Gait Analysis" by Kenneth D. Taylor et al, published in Biomechanics, Vol. 15, No. 7, pp 505-516, 1982. This article describes an automated motion measuring system which employs a television camera interfaced to a computer. The system was constructed to evaluate clinical gait analysis. The system employs passive markers which are placed on a human torso which torso is illuminated with infrared light emitting diodes.
This approach according to the article minimizes patient distraction since the illumination is not visible and reduces patient discomfort. In any event, the motion measurement system has been employed and purportedly operates to perform the required task. The abovenoted article has a relatively extensive bibliography which references various other prior art systems which employ television cameras and tape recorders to record motion data. Essentially, the use of computers in general for tracking body motions is well known in the prior art and there are many other examples of such devices.
See for example an article entitled "Computer Aided Tracking Of Body Motion Using A C.C.D.-Image Sensor" by W. Brugger et al, published in Medical And Biological Engineering and Computers, Vol. 16, pp 207-210, March 1978. In that particular article there is described an image sensor which is employed to obtain on-line trajectories of moving objects in one plane. The image data acquired is stored and processed by several programs to yield displays which enable interpretation and measurements to be effected.
One aspect of the particular application of the system is in regard to kinesiological data allied with human locomotive functions. The prior art includes many patents related to motion analysis such as U.S. Pat. No. 4,375,674 issued on Mar. 1, 1983 to W. E. Thornton and entitled KINESIMETRIC METHOD AND APPARATUS. This patent discloses apparatus and methods for determination of functional capability of bodies. Certain aspects such as reach as well as velocity, acceleration and force generation at various positions are determined for a body by a three-dimensional kinesimeter equipped with an ergometer.
Thus, the patent shows techniques for measuring various trajectories provided by human movement which techniques employ television cameras to gather and process data.
Pursuant to such prior art approaches, reference is also made to U.S. Pat. No. 4,631,676 which issued on Dec. 23, 1986 to James W. Pugh and entitled COMPUTERIZED VIDEO GAIT AND MOTION ANALYSIS SYSTEM AND METHODS. In that patent there is described a system which employs reflective markers attached to the front side of particular joints of a subject whose motion or gait is to be analyzed. Each marker as indicated is formed of a reflective tape and is small so as not to hinder the subjects motion. The patent discloses and uses a pair of commercial video motion analyzers which operate at 60 frames per second and are positioned to the front and side of a walk path or runway.
The monitors coact with video cassette tape recorders which record the patient's movements along the runway. There are monitors which are provided for playback of the recorded video tape and include built-in magnetic disks allowing 10 seconds of a nigh speed motion to be recorded and displayed. The structure includes a video analysis board which essentially is a minicomputer and operates to digitize each recorded video frame to locate centroids of each of the reflective markers. This data is fed into a computer which operates on the data to provide line and stick figure displays of the data and which operate to depict the motions under study. Various other diagrams such as cyclograms of hip angle-knee angle relations for a cycle of movement are provided. As one can ascertain from this reference, there are various figures which show desirable outputs which are utilized by practitioners to study the gait of a particular patient as well as to provide other displays which are useful in analyzing motion.
In any event, as one can ascertain from the prior art, such systems which are operative to provide motion analysis are largely dependent upon processing techniques as well as requiring extensive software and computer time in order to solve such problems. There are substantial problems involved in acquiring analyzed data in conjunction with video tape recorders as well as employing computer processing techniques. Certain of these, as indicated above, can be circumvented by the use of algorithms.
In any event, various algorithms for such motion analysis are well known in the prior art. Such algorithms are intended for resolution of problems that include various discrepancies in video signals such as missing data points, statistical techniques to improve accuracy, searching routines and calibration programs. Such algorithms as indicated have been widely employed in the prior art to enhance the use of such systems.
In spite of the strides made in motion analysis according to such prior art techniques, there are many problems which still have to be solved. Such problems mainly relate to the complexity of the prior art systems and the extreme difficulty in reducing the cost and time involved in compiling and analyzing the data. As indicated, while most systems generally employ a video camera in conjunction with tape recorders and computers the adaptability is a pure function of the manner in which the data is analyzed as well as the various problems associated with tape recorders and video monitors. These operate in conjunction with computers in an attempt to establish proper and reliable operating levels in order to provide valid data indicative of the motion to be analyzed.
It is therefore an object of the present invention to provide a motion analysis system which is relatively inexpensive and which enables an accurate presentation of motion in real time.
It is a further object to provide a system which operates to eliminate many of the problems associated with the prior art.
Thus, the system to be described employs various unique techniques in order to assure reliability such as techniques for providing accurate synchronization between the various components, techniques for analyzing the proper location of various marking devices in order to provide proper graphic presentation of data and as well as other techniques.
As will be explained, the present invention also is capable of operating in various modes whereby in a first mode one can obtain pressure information concerning forces applied to the foot of a patient in regard to the toe heel and arch area when the patient is walking. Another mode of operation which can also be utilized in conjunction with the above mode enables one to provide accurate presentations in terms of stick figures of the gait of such a patient. This data therefore enables the practitioner to get an accurate and reliable view of a patient's gait in order to help the patient solve the problems that he may have.